When people say that someone seems like they're "from another planet," they usually mean that the person's behavior or characteristics are so unusual or different that it's hard to relate to them or understand their perspective.
It's not uncommon for people to encounter individuals who have unique or eccentric traits that make them stand out or appear different from societal norms. Sometimes, these individuals may have distinctive personalities, unconventional ideas, or unusual ways of expressing themselves. However, it's important to remember that diversity and individuality are part of what makes our world interesting and vibrant. Embracing and appreciating our differences can lead to a greater understanding and acceptance of others.